CN106061854B

CN106061854B - For covering and the polymer composition of closure member

Info

Publication number: CN106061854B
Application number: CN201580012345.1A
Authority: CN
Inventors: B.科赫; C.穆瓦诺
Original assignee: Ineos Europe AG
Current assignee: Ineos Europe AG
Priority date: 2014-01-06
Filing date: 2015-01-05
Publication date: 2018-11-09
Anticipated expiration: 2035-01-05
Also published as: BR112016015796B1; US20160333172A1; US9976017B2; CN106061854A; RU2682184C2; WO2015101668A1; EP3092180B1; KR102250023B1; EP3092180A1; KR20160106660A; CA2936812C; RU2016132399A; BR112016015796A8; CA2936812A1; RU2016132399A3; BR112016015796A2

Abstract

The polyethylene composition suitable for being prepared into lid and closure member is described, with 950-960kg/m³Density, the SHI of 4-12_(1/100), the melt index MI of 0.2-2g/10min₂, E>Relationship between the spiral flow ' SF ' (being measured with mm at 250 DEG C/1000 bars/100mm/s) and ESCR ' E ' (being measured with hour) of 200-SF, or alternatively there is 950-960kg/m³Density, the SHI of 4-12_(1/100), the melt index MI of 0.2-2g/10min₂And E>(9800-36SF-1000MI₂Spiral flow ' SF ', ESCR ' E ' and the melt index ' MI of)/60₂' relationship between (being measured with g/10min according to ISO 1133 under the load of 2.16kg at 190 DEG C).

Description

For covering and the polymer composition of closure member

The present invention relates to new ethylene polymer composition and it is related to product prepared therefrom, is prepared especially by injection molding Product, such as lid and closure member.

Injection molding can be used for preparing various products, include the product with relative complex shapes and sizes range. Especially important application is manufacture lid and closure member, is used for food and beverage application, such as containing carbonic acid or noncarbonated beverage products Bottle, or for the container of non-food applications such as cosmetics or drug.

The critical nature of polymer to be molded is its rheological characteristic, rigidity, environmental stress crack resistance (ESCR) and sense organ Property needs while meeting to its all requirement.Injection-molded item, especially lid and closure member, can with aggressive food products and Non-food stuff media contact and/or be subjected to external stress, such as in the lid as carbonated soft drink, and high ESCR be therefore in accordance with It needs.High ESCR values are generally obtained with the polyethylene compared with low-density and/or compared with low melt index.On the other hand, injection-molded item High rigidity is also needed to, since this allows to reduce wall thickness, while keeping good dimensional stability.Rigidity generally with density improve and It improves.

In injection molding it is also important that polymer melt have the suitable rheological equationm of state, i.e., mobility within certain limits, To ensure that the property of final products is desirable.For example, the mobility of polymer melt must be high enough that it is being noted The all areas of mold can be flow to when penetrating to form the product of needs.In addition, the flow velocity of polymer melt is higher, it can Bigger and process time is shorter with the speed being injected into mold, this improves productivity.The especially relevant mobility with injection molding It is measured as spiral flow, measures molten polymer under specific pressure, temperature and injection rate around the length of the spiral of flowing Degree.Higher spiral flow indicates preferable machinability.

In order to improve flowing property, it is typically selected to have wider molecular weight distribution or with the poly- second compared with high fusion index Alkene.However, tending to produce the product with difference ESCR with the polymer compared with high fusion index.In addition, with wide molecular weight The polymer of distribution may further result in the larger degree of orientation of the polymer chain in the injection-molded item of completion, this can facilitate it is above-mentioned compared with Poor engineering properties.Therefore polyethylene with Narrow Molecular Weight Distribution and low melt index is more suitable for using good flow properties as generation Valence reaches desired environmental stress crack resistance.

In order to improve the rigidity of end article such as lid, the density for improving polymer is well known.However higher density inclines To in leading to poor ESCR.

Moreover, especially with respect to the food applications of lid and closure member, it is important that composition has good taste and odor profiles Matter and the low-level extractable that can be moved in food.It is preferred that narrower molecular weight distribution, since it indicates composition In small percentage very low molecular weight material, lead to the less volatile fraction that can migrate in food.

Our own EP 1441959A illustrations are used to cover and the bimodal polyethylene composition of closure member, with 951- 953kg/m³The density of range, the MI of 0.6-1.7g/10min ranges₂Value, about 50:50 LMW:HMW component ratios.Report as The ESCR-B values higher than 1000h measured on compression molding sample, but it is not reported in the ESCR data that injection covers acquisition. SHI is not disclosed_1/100Or spiral flow valuve.

WO 2007/130515 disclose suitable for cover with the polyethylene composition of closure member, with 950-960kg/m³ Density and preferred 1-2g/10min MI₂And g '> 1.

EP 1655338A are disclosed for covering and the polyethylene composition of closure member, with 0.1-100g/10min's MI₂, at least 3kJ/m²23 DEG C of charpy impact intensity and SHI_1/100With log MI₂Between particular kind of relationship.All present invention Embodiment be multimodal, there is at least 961kg/m³Density and 8-14 SHI_1/100。

EP 1655336A are also disclosed having 0.1-100g/ for covering with the polyethylene composition of closure member, this one kind The MI of 10min₂, the ESCR and SHI of at least ten hour_1/100With log MI₂Between different relationships.The reality of all present invention It is multimodal to apply example, has 956kg/m³-961kg/m³Density and 14-22 SHI_1/100。

EP2017302A is disclosed for covering with the hexene copolymer of closure member, the MI with 0.1-100g/10min₂, Stretch modulus>850MPa, the ESCR-B and at least 15kJ/m of at least 300 hours²23 DEG C of charpy impact intensity.It is all Embodiment has the molecular weight distribution (Mw/Mn) of 15-22.

WO2011004032 disclose comprising two polyethylene part A and B with metallocene catalyst prepare for covering With the bimodal polyethylene composition of closure member, part A is substantially free of comonomer and provides environmental stress crack resistance, sense organ Improvement balance between property, dimensional stability, matched compactness and the easiness of opening.All the embodiment of the present invention are special Sign is Narrow Molecular Weight Distribution (Mw/Mn< 5).

WO2007018720 discloses the use for including two polyethylene part A and B preferably prepared with metallocene catalyst In the bimodal polyethylene composition of injection molding.The preferred molten index of blend is at least 4g/10min, and the embodiment combines height Total melt index in 4g/10min and the parts HMW at least melt index of 0.46g/10min（It, which is equal to, is higher than The HLMI of 10g/10min）.It is anti-with relative mistake that the parts HMW with high fusion index/low molecular weight generally result in composition Stress cracking resistance.

We have now found that new polyethylene composition, with good workability, high rigidity, good ESCR and it is low can The particularly advantageous combination of extract.

The present invention provides a kind of polyethylene compositions, with 950-960kg/m³Density, the SHI of 4-12_1/100, The melt index MI of 0.2-2g/10min₂And E>200-SF spiral flow ' SF ' (at 250 DEG C/1000 bars/100mm/s with Mm is measured) relationship between ESCR ' E ' (being measured with hour).

It is preferred that the composition has E>370-2SF and most preferably E>The spiral flow ' SF ' and ESCR ' E ' of 540-3SF Between relationship.

At an alternative aspect, the present invention provides polyethylene compositions, with 950-960kg/m³Density, 4-12 SHI_1/100, the melt index MI of 0.2-2g/10min₂And E> (9800-36SF-1000MI₂)/60 and preferred E> (11000-36SF-1000MI₂)/60 and more preferable E> (12000-36SF-1000MI₂)/60 spiral flow ' SF ' ( Measured with mm under 250 DEG C/1000 bars/100mm/s), ESCR ' E ' (being measured with hour) and melt index ' MI₂' (at 190 DEG C Under measured with g/10min according to ISO 1133 under the load of 2.16kg) between relationship.

Hereafter all features are suitable for the invention above-mentioned two aspect.

For purposes of the present invention, MI is measured according to ISO 1133 under the load of 2.16kg at a temperature of 190 DEG C₂。

The spiral flow ' SF ' (being measured at 250 DEG C/1000 bars/100mm/s) of polyethylene composition is preferably greater than 10mm, More preferably greater than 35mm and most preferably greater than 60mm.SF is also preferably less than 190mm, more preferably less than 180mm and more preferably less than 175mm。

In one embodiment of the invention, the polyethylene composition preferably have 1-2g/10min, more preferably The MI of 1.2-1.8g/10min₂。

In the alternative embodiment of the present invention, the polyethylene composition preferably has 0.1-1g/10min, more It is preferred that the MI of 0.2-0.8g/10min₂。

In one embodiment of the invention, the polyethylene composition preferably has 954-960kg/m³And most especially It is 955-959kg/m³Density.

In another embodiment of the present invention, the polyethylene composition preferably has 950-954kg/m³And it is most special It is not 951-954kg/m³Density.

In a preferred embodiment, the polyethylene composition has 954-960kg/m³Density and 0.1-1g/ The MI of 10min₂, preferably 955-959kg/m³Density and 0.2-0.8g/10min MI₂。

In an alternative preferred embodiment, the polyethylene composition has 950-954kg/m³Density and 1- The MI of 2g/10min₂, preferably 951-954kg/m³Density and 1.2-1.8g/10min MI₂。

Hereafter all features are suitable for the invention all embodiments of both sides.

The SHI of the polyethylene composition_(1,100)For preferred 4-10, more preferable 4-8.

The molecular weight distribution (Mw/Mn) (being measured by gpc analysis) of the composition is preferred 5-13, more preferable 6-12 And most preferably 7-11.

The g ' of the polymer composition is preferably less than 1, methods of the wherein g ' according to WO 2007/130515 It determines.

The composition has S<0.1SF, preferably S<0.1SF-2.5 and most preferably S<The spiral flow of 0.1SF-5 Relationship between ' SF ' (being measured with mm at 250 DEG C/1000 bars s/100mm/s) and soluble matter ' S ' (being measured with g/kg).

The polyethylene composition of the present invention is preferably multimodal, since it includes at least two polyethylene components.Most preferably its To be bimodal, this indicates that it includes only two kinds of polyethylene components of significant quantity.The form of the molecular weight distribution curve of multimodal polyethylene (i.e. the appearance of the chart of the functional relation of polymer weight fractin and its molecular weight) will show two or more maximum values or At least obviously widen compared with the curve of unitary part.For example, if polymer utilizes in continuous multi-stage method each The reactor production of coupled in series with different condition, each polymer moieties generated in different reactor in a reactor It will be with itself molecular weight distribution and weight average molecular weight.The molecular weight distribution curve of such polymer includes the part Independent curve summation, generally produce with substantially unimodal or two or more different maximum values multimodal polymer Curve." substantially unimodal " can not follow Gaussian Profile, can be wider than indicated by Gaussian Profile, or with than Gaussian Profile More flat peak.Some substantially unitary peaks can have tail portion in the either side at peak.Pass through various sides in some embodiments It will be possible that " substantially unimodal " in molecular weight distribution curve is mathematically split into two or more components by method.

It is preferred that the composition of the present invention includes the ethylene copolymer of ethene polymers (A) and 38-52wt% of 48-62wt% (B), copolymer (B) has weight average molecular weight more higher than polymer (A).The more preferable composition includes the second of 50-60wt% The ethylene copolymer (B) of alkene polymer (A) and 40-50wt%, and most preferably it includes the ethene polymers of 54-60wt% (A) and The ethylene copolymer (B) of 40-46wt%.

The polyethylene composition can optionally further include the small of the 10wt% or less amounts based on whole polyethylene Prepolymerization part.Alternatively or additionally, the part of very heavy polymer can be further included, have than The above-mentioned higher molecular weight of heavy polymer is 10wt% or less amounts based on whole polyethylene.

Generally preferably be the total amount no matter the various polymer in composition, and presence or absence of any other The weight ratio of polyethylene part, polymer (A) and polymer (B) in polyethylene composition is 48:52-62:38, more preferably 50:50-60:40 and most preferably 54:46-60:40.

Ethene polymers (A) can be homopolymer or ethylene and C₄-C₈The copolymer of alpha-olefin.Ethene polymers (B) is second Alkene and C₄-C₈The copolymer of alpha-olefin.

Based on whole polyethylene, the amount of polymer present in composition (A) is preferably 48wt%-62wt%, more preferably 50wt%-60wt% and most preferably 54wt%-60wt%.The amount of polymer present in composition (B) is preferably 38wt%-52wt%, More preferable 40wt%-50wt% and most preferably 40wt%-46wt%.These be only two polyethylene parts present in composition In the case of, this tittle corresponds to the weight ratio of (A) and (B).It however as described above, can be optionally poly- in the presence of other in the composition Ethylene moiety：When the amount of polymer (A) and polymer (B) is respectively 53-62wt% and 38-47wt%, preferably as described above The maximum of any prepolymer is 5wt%, and the maximum of any very high molecular weight moieties as described above is 5wt%.

For purposes of the present invention, it should be understood that term " homopolymer " indicates substantially by the monomeric unit structure of ethylene derivative At and substantially free of the ethene polymers of the monomeric unit derived from other polymerizable olefins.It can include can by other Micro unit derived from olefin polymerization, other described polymerizable olefins are present in following again for charging or polymerization as impurity It is carried between stage in circulation or in multi-stage method, but it should repeat list comprising at least about 99.7% mole of ethylene Member, based on all repetitive units present in " homopolymer ".It should understand that term " ethylene and C₄-C₈The copolymer of alpha-olefin " table Show comprising by the monomeric unit of ethylene derivative and by C₄-C₈It is alpha-olefin derived and optionally other are alpha-olefin derived by least one The copolymer of monomeric unit.C₄-C₈Alpha-olefin can be selected from the ethylenically unsaturated monomer for including 4-8 carbon atom, for example, 1- fourths Alkene, 1- amylenes, 1- hexenes, 3-methyl-1-butene, 3- and 4-methyl-1-pentene and 1- octenes.It is preferred that alpha-olefin be 1- butylene, 1- hexenes and 1- octenes and more particularly 1- hexenes.In addition to C₄-C₈Except alpha-olefin, there may also be other alpha-olefins it is preferred Selected from the ethylenically unsaturated monomer for including 3-8 carbon atom, for example, propylene, 1- butylene, 1- amylenes, 3-methyl-1-butene, 3- With 4-methyl-1-pentene, 1- hexenes and 1- octenes.

In copolymer (B) by C₄-C₈The content of alpha-olefin derived monomeric unit, hereinafter referred to as co-monomer content, one As be at least 0.1mol%, especially at least 0.4mol%.The co-monomer content of copolymer (B) is usually from most 3mol%, preferably Most 2mol%.Co-monomer content in all compositions is preferably 0.1-1mol% ranges, preferably 0.1-0.8mol% ranges and Most preferably 0.2-0.5 mol% ranges.

The feature of the composition of the present invention is preferably substantially uniform or anti-in part one or both of (A) and (B) To comonomer distribution.Reversed comonomer distribution is that the specific co-monomer content of unitary part is distributed, which part (A) Or the lower molecular weight end of (B) with compared with low co-monomer content and the higher molecular weight end of the part is with proportional higher Co-monomer content：In other words, co-monomer content is improved with the raising of molecular weight in unitary part.This and typical polymerization For object on the contrary, the molecular weight of copolymer portion is lower in conventional polymer, co-monomer content is higher.Homogeneous comonomer point The entire width that cloth is limited to the molecular weight distribution wherein in polymer moieties is not present and increases or decreases the comonomer of trend Distribution.Homogeneous comonomer, which is distributed, can alternatively be limited to indicate on the molecular weight ranges of specific part, polymer moieties Co-monomer content variation be less than 10wt%, preferably smaller than 8%, more preferably less than 5%, and more preferably less than 2%, this is indicated in spy Determine on the molecular weight ranges of part, the average value of highest and lowest co-monomer content and the co-monomer content of the part is inclined From less than 10% (and more preferably less than 2%).For example, if the average comonomer content in specific part is 2wt% and copolymerization is single Body changes of contents is less than 0%, then peak is no more than 2.2wt% and minimum is more than 1.8wt%.

In one embodiment of the invention, composition of the invention is characterized as part one or both of (A) and (B) The comonomer distribution of middle substantial reverse.

The characteristic of comonomer distribution can be determined by measuring the functional relation of co-monomer content and molecular weight.This can To be carried out to Waters 1500C gel permeation chromatographies (GPC) by coupling Fourier Transform Infrared Spectroscopy (FTIR).The system Configuration, calibration and operation and for data processing method previous description (L.J. Rose et al., "Characterisation of Polyethylene Copolymers by Coupled GPC/FTIR（Pass through connection GPC/FTIR characterizes polyethylene and ethylene copolymers）"in "Characterisation of Copolymers", Rapra Technology, Shawbury UK, 1995, ISBN 1-85957-048-86.).Other details can be our own It is found in EP 898585A.

For purposes of the present invention, C₄-C₈Alpha-olefin content passes through¹³C NMR are according in J.C. Randall, JMS-Rev. Macromol. Chem. Phys., C29 (2&3), method described in the 201-317 pages (1989) measure, that is to say, that by C₄-C₈The content of alpha-olefin derived unit is by compared with the integral (30ppm) of the line feature of the unit from ethylene derivative, the spy Determine C₄-C₈The survey calculation of the integral of the line feature of alpha-olefin.Composition substantially by being constituted from the monomeric unit of ethylene derivative and Particularly preferably single C₄-C₈Alpha-olefin.Preferred single C₄-C₈Alpha-olefin is selected from 1- butylene, 1- hexenes and 1- octenes；1- oneself Alkene is particularly preferred.

It is preferred that the polymer (A) in multimodal composition has the MI of 10-800g/10min, preferably 200-700g/10min₂。 The MI of polymer (A)₂More preferable ranging from 200-500g/10min, and most preferred range be 250-450g/10min.

In one embodiment of the invention, the ethene polymers (A) has 969-974kg/m³, preferably 969- 973kg/m³, most preferably 970-973kg/m³Density.Preferred polymers (A) are ethylene and C₄-C₈The copolymer of alpha-olefin.

In a preferred embodiment of the invention, the ethene polymers (A) has 969-974kg/m³Density With the MI of 10-800g/10min₂, preferably 969-973kg/m³Density and 200-500g/10min MI₂, and most preferably 970- 973kg/m³Density and 250-450g/10min MI₂。

In one embodiment of the invention, wherein the polyethylene composition has 950-954kg/m³And more preferably 951-954kg/m³Density, the density of the copolymer (B) is 919-936kg/m³And most preferably 924-932kg/m³.At this In embodiment, the HLMI of copolymer (B) is preferably 3-6g/10min, more preferable 4-5g/10min：Alternatively, copolymer (B) MI₂For preferred 0.1-0.2g/10min, more preferable 0.12-0.18g/10min.It is preferred that the copolymer (B) has 924- 932kg/m³Density and 4-5g/10min HLMI or 0.12-0.18g/10min MI₂.Further preferably whole polyethylene compositions MI with 1-2g/10min, more preferable 1.2-1.8g/10min₂。

In the alternative embodiment of the present invention, wherein the polyethylene composition has 954-960kg/m³And more It is preferred that the density of 955-959kg/m³, the density of the copolymer (B) is 929-947kg/m³, and preferred 934-942kg/m³.? In the embodiment, the HLMI of the copolymer (B) is preferred 0.2-2g/10min, most preferably 0.5-1.5g/10min：It can replace Dai Di, the MI of the copolymer (B)₂For preferred 0.01-0.08g/10min, most preferably 0.02-0.05g/10min.It is preferred that being copolymerized Object (B) has 934-942kg/m³Density and 0.5-1.5g/10min HLMI or 0.02-0.05g/10min MI₂.It is also excellent The whole polyethylene compositions of choosing have the MI of 0.1-1g/10min, more preferable 0.2-0.8g/10min₂。

If polymer (A) and (B) are prepared separately and are then blended, the melting that can directly measure two kinds of polymer refers to Number, density and co-monomer content.However, if a kind of polymer is prepared in another previously wherein and subsequent second polymerize Multimodal polymer is prepared in the multi-stage method that object is prepared in the presence of first polymer, then the melting of second polymer refers to Number, density and co-monomer content are unable to measure, and on the contrary, for purposes of the present invention, they are as defined below.Hereafter Restriction will apply also for the third prepared in the presence of first two polymer or subsequent polymer (if present).

All melt index, for example, second (or third or subsequent) polymer HLMI and MI₂Be limited to when with In prepare be prepared separately under the identical polymerizing condition of multimodal composition when (or third or subsequent) polymer is direct for second The value of measurement.In other words, second (or third or subsequent) polymer is using same catalyst and in the polymerize with multimodal It is prepared separately under identical polymerizing condition those of employed in two (or third or subsequent) reactors, and it is molten then to measure it Melt index.Optionally, second the melt index of (or third or subsequent) polymer can also use composition law meter It calculates, usually common version

,

Wherein k is empirically determined, such as by using the two sseparated reactions that can directly measure melt index wherein The blend composition prepared in device.The example of such law is described in " Prediction of melt flow rate (MFR) of bimodal polyethylenes based on MFR of their components（Based on bimodal poly- second The MFR of melt flow (MFR) the prediction bimodal polyethylene of the component of alkene）", Bengt Hagström, Conference of Polymer Processing in Gothenburg, 19-21/08/1997.In some cases, MI₂It may too low and nothing Method general measure：In these cases, MI is measured₅Or high load melt index (I₂₁), and the value is converted to MI of equal value₂。 This conversion between difference melt index measurement familiar to the person skilled in the art.

The density limitations of second (or third or subsequent) polymer are to be calculated by following relationship：

Density (composition)=

Wherein x is the weight fraction of component n, and d is the density of component n, and the number that n is the polymer in composition.

The co-monomer content of second (or third or subsequent) polymer is limited to be calculated by following relationship：

Co-monomer content (composition)=

Wherein x is the weight fraction of component n, and c is the co-monomer content of component n, and n is the polymer in composition Number.

If polymer is prepared with " multi-catalyst system " such as bimetallic catalyst, can be prepared in same reactor Two kinds of polymer (A) and (B).In this case, it is not possible to directly measure polymer (A) or polymer (B) is any Property.Therefore in this case, the property of polymer (A) and (B) the two is limited to use " more catalysis in corresponding polymer The single catalyst of agent system " and be used to prepare those identical polymerizing conditions used by multimodal polymer compositions under Those of obtained when being prepared separately.

Although the present invention composition can be made of completely above-mentioned polyethylene, the present invention include within its scope comprising except The composition of other components except polyethylene.Specifically, the composition can include the total weight based on composition At most 10wt%, preferably up to 5wt% and the amount of more preferably up to 3wt% conventional additives.Such additive includes stablizing Agent (antioxidant and/or anti-UV agent), antistatic agent and processing aid and pigment.The composition may also contain up to Another polyolefin of 10wt%.

The preferred multimodal polyethylene composition of the present invention can be generated by any methods known in the art：Such as machinery Polymer blend (A) and (B) and optionally other polyethylene, polymer (A) is formed in situ in the presence of " multi-catalyst system " (B), and polymer (A) and (B) is formed in multi-stage method.Being blended can carry out in any conventional intermingling apparatus.

" multi-catalyst system " indicates the composition, mixture or the system that include at least two different catalysts compounds, Respectively there is identical or different metal group, including " dual catalyst ", for example, bimetallic catalyst.Use multi-catalyst system Multimodal product can be prepared in single reactor.The various different catalysts compounds of multi-catalyst system may be at single On carrier granular, think that bis- (bimetallic) catalyst are catalyst-loaded in said case.However, term bimetallic catalyst Also include that wherein one of catalyst is on a kind of vector particle aggregation body and another catalyst is in another carrier extensively System on particle aggregate or mixture.Preferably, catalyst-loaded while or sequentially by two kinds in the case of the latter It is introduced into single reactor, and is gathered in the presence of bimetallic catalyst system i.e. two kind carried catalyst aggregation It closes.Alternatively, multi-catalyst system includes the mixture of the unsupported of slurry form.A kind of catalyst can be used for HMW components are generated, and other can be used for generating LMW components.LMW catalyst usually than HMW catalyst to chain termination reagent more There are response, such as hydrogen.

However the polyethylene composition of the present invention is preferably obtained by multistage vinyl polymerization usually using series reaction device ?.Multi-stage method is a kind of polymerization, wherein the polymer comprising two or more parts passes through in separated reaction Stage（Usually in differential responses condition of each stage）In, in the presence of the reaction product of previous stage generate at least two Polymer moieties generate.Polymerisation used in each stage may include conventional ethylene homopolymerization or copolyreaction, such as Gas phase, slurry phase, liquid phase polymerization, use conventional reactor, such as loop reactor, gas-phase reactor, batch reactor etc..

It is preferred that the polymer (A) generates in the first reactor, and polymer (B) generates in subsequent reactor. However this sequence can be opposite.If the pre-polymerization that multimodal composition is prepared included in the reactor before first reactor Object.It is preferred that all reactors are slurry reactor, especially slurry circuits reactor.

In a particularly preferred multistage polymerization method：

In the first reactor, ethylene and optional C₄-C₈Alpha-olefin comonomer comprising diluent, hydrogen, based on transition gold With slurry polymerisation in the catalyst of category and the first mixture of co-catalyst, it is relative to the total weight of composition to be formed The Alathon or copolymer (A) of 45-55% weight；

First mixture taken out from the reactor and withstanding pressure reduce, to make at least part hydrogen degassing with The mixture at least partly to deaerate is formed, and by the mixture at least partly to deaerate, with ethylene and C₄-C₈Alpha-olefin and Other optional at least one alpha-olefins are introduced together into subsequent reactor and carry out slurry polymerisation wherein to form phase Total weight for composition is the ethylene and C of 45-55% weight₄-C₈The copolymer of alpha-olefin.

The present invention also provides the methods for obtaining injection-molded item comprising following steps：Keep ethylene and optionally copolymerization single Body polymerize, and the polyethylene composition is made to mix, and then makes the composition injection molding to form product.The step of polymerising ethylene It is preferably formed as multimodal polyethylene.

It can be suitable for preparing these that the catalyst of the polyethylene composition to generate the present invention is used in polymerization Any catalyst of polyethylene.If fruit polyethylene is multimodal, preferably same catalyst generates both high and low molecular weight parts.Example Such as, the catalyst can be Ziegler-Natta catalyst or metallocene catalyst.It is preferred that the catalyst is metallocene catalysis Agent.

It is preferred that the composition of the present invention is prepared using metallocene catalyst system, and most preferred metallocene is to generally comprise Those of monocyclopentadienyl metallocene complex and suitable activator with " limitation geometry " configuration.Suitable for this hair The example of bright monocyclopentadienyl or substituted new monocyclopentadienylcomplex complex be described in EP 416815, EP 418044, In EP 420436 and EP 551277.

Suitable complex compound can be indicated by general formula：

CpMX_n

Wherein Cp is that the single cyclopentadienyl group of M or substituted cyclopentadienyl group, M are optionally covalently attached to by substituent group For with η⁵Bonding scheme is connected to the IVA races metal of cyclopentadienyl group or substituted cyclopentadienyl group, and X occurs every time for extremely The hydride of more 20 non-hydrogen atoms is selected from halogen, alkyl, aryl, aryloxy group, alkoxy, alkoxyalkyl, acylamino- alkane The part of base, siloxyalkyl etc. and with the neutral Lewis base ligands of at most 20 non-hydrogen atoms or an optional X The becket compound with M is formed with together with Cp and chemical valences of the n depending on metal.

It is preferred that new monocyclopentadienylcomplex complex has formula：

Wherein：-

R ' occurs being independently selected from hydrogen, alkyl, silicyl, germyl, halogen, cyano and combinations thereof, the R ' every time With at most 20 non-hydrogen atoms, and optionally, two R ' groups (wherein R ' is not hydrogen, halogen or cyano) form be connected to together The adjacent position of cyclopentadienyl rings is to form its divalent derivative of condensed cyclic structure；

X is hydride at most 20 non-hydrogen atoms or selected from halogen, alkyl, aryl, aryloxy group, alkoxy, alkane The part of oxygroup alkyl, amidoalkyl, siloxyalkyl etc. and neutral Louis at most 20 non-hydrogen atoms Aar ligand,

Y be-O- ,-S- ,-NR*- ,-PR*-,

M be hafnium, titanium or zirconium,

Z* is SiR*₂、CR*₂、SiR*₂SiR*₂、CR*₂CR*₂、CR*=CR*、CR*₂SiR*₂Or GeR*₂, wherein：

R* occurs standing alone as hydrogen or member selected from the following every time：Alkyl, silicyl, halogenated alkyl, halogenated aryl and A combination thereof, the R* have at most 10 non-hydrogen atoms, and optionally, two R* groups (when R* is not hydrogen) from Z*, or R* groups from Z* and the R* groups from Y form member ring systems,

And n is 1 or 2, depends on the chemical valence of M.

The example of suitable new monocyclopentadienylcomplex complex is (t-butylamido) dimethyl (tetramethyl-η⁵Ring penta 2 Alkenyl) silane titanium chloride and (2- methoxyphenyls acylamino-) dimethyl (tetramethyl -- η⁵Cyclopentadienyl group) silane dichloro Change titanium.

Being used to prepare the particularly preferred metallocene complex of the copolymer of the present invention can be indicated by general formula：

Wherein：-

X is the neutral η at most 30 non-hydrogen atoms⁴It is bonded diene group, π-complex compound is formed with M；

Y be-O- ,-S- ,-NR*- ,-PR*-,

M is the titanium or zirconium in+2 form oxidation state；

R* occurs standing alone as hydrogen or member selected from the following every time：Alkyl, silicyl, halogenated alkyl, halogenated aryl and A combination thereof, the R* have at most 10 non-hydrogen atoms, and optionally, two R* groups (when R* is not hydrogen) from Z*, or R* groups from Z* and the R* groups from Y form member ring systems.

The example of suitable X group includes the trans--η of s-⁴- 1,4- diphenyl -1,3- butadiene；Trans--the η of s-⁴- 3- methyl- 1,3- pentadienes；Trans--the η of s-⁴- 2,4- hexadienes；Trans--the η of s-⁴- 1,3- pentadienes；Trans--the η of s-⁴Xylyl-1-1,4-, 3- butadiene；Trans--the η of s-⁴Bis- (the trimethyl silyl) -1,3- butadiene of -1,4-；Cis--the η of s-⁴- 3- methyl-1s, 3- penta 2 Alkene；Cis--the η of s-⁴- 1,4- dibenzyl -1,3- butadiene；Cis--the η of s-⁴- 1,3- pentadienes；Cis--the η of s-⁴Bis- (the front threes of -1,4- Base silicyl) -1,3-butadiene, the cis- diene groups of s- as text defined in metal formed π-complex compound.

Most preferably R ' be hydrogen, methyl, ethyl, propyl, butyl, amyl, hexyl, benzyl or phenyl or 2 R ' groups (in addition to Except hydrogen) it links together, entire C₅R’₄Thus group is, for example, indenyl, tetrahydro indenyl, fluorenyl, tetrahydrofluorenyl or octahydro fluorenes Base.

Highly preferred Y group is containing corresponding to formula-N (R^//)-or-P (R^//)-group nitrogenous or phosphorus group, wherein R^//For C_1-10Alkyl.

Most preferred complex compound is two base complex of amidosilanes-or acylamino- alkane.

It is those of titanium that most preferred complex compound, which is wherein M,.

Specific complex compound is those disclosed in WO 95/00526, and is incorporated by reference into text.

Particularly preferred complex compound is (t-butylamido) (tetramethyl-η⁵Cyclopentadienyl group) dimethylsilane titanium-η⁴- 1.3- pentadiene.

The suitable cocatalysts for being used to prepare the new copolymer of the present invention are usually together with above-mentioned metallocene complex Those of use.

These include aikyiaiurnirsoxan beta such as methylaluminoxane (MAO), such as three (pentafluorophenyl group) borine of borine and borate.

Aikyiaiurnirsoxan beta is well known in the art and preferably comprises oligomeric linear and/or naphthenic base aikyiaiurnirsoxan beta.Aikyiaiurnirsoxan beta can be with Many modes prepare and preferably by contacting water and trialkyl aluminium compound in suitable organic media such as benzene or aliphatic hydrocarbon Such as prepared by trimethyl aluminium.

Preferred aikyiaiurnirsoxan beta is methylaluminoxane (MAO).

Other suitable co-catalysts are organoboron compound, especially triarylboron.Particularly preferred three virtue Base boron compound is three (pentafluorophenyl group) borines.

Other compounds for being suitable as co-catalyst are the compound comprising cation and anion.The cation is logical Often for can contribute proton Bronsted acid and the anion be usually be capable of stable cationic compatible noncoordinating big Volume species.

Such co-catalyst can be indicated by following formula：

(L*-H)⁺ _d(A^d-)

Wherein：-

L* is the lewis base of neutrality

(L*-H)⁺ _dFor Bronsted acid

A^d-For with d^-The noncoordinating Compatible anions of charge, and

D is the integer of 1-3.

The cation of ionic compound can be selected from：Acid cation, carbonCation, silicylCation, oxygenCation, organometallic cation and cation oxidant.

It includes the ammonium cation replaced by trialkyl, such as triethyl ammonium, tripropyl ammonium, three to be suitble to preferred cation (normal-butyl) ammonium and analog.Also suitably from N, N- dialkylanilinium, such as N, N- dimethylanilinium cation.

Preferred ionic compound as co-catalyst is that the cation of its mesoionic compound includes to be replaced by alkyl Ammonium salt and anion include those of the borate being substituted with aryl.

The Typical borates for being suitable as ionic compound include：

Tetraphenylboronic acid triethyl ammonium

Tetraphenylboronic acid triethyl ammonium,

Tetraphenylboronic acid tripropyl ammonium,

Tetraphenylboronic acid three (normal-butyl) ammonium,

Tetraphenylboronic acid three (tertiary butyl) ammonium,

Tetraphenylboronic acid N, N- dimethyl puratized agricultural spray,

Tetraphenylboronic acid N, N- diethyl puratized agricultural spray,

Four (pentafluorophenyl group) boric acid trimethyl ammoniums,

Four (pentafluorophenyl group) boric acid triethyl ammoniums,

Four (pentafluorophenyl group) boric acid tripropyl ammoniums,

Four (pentafluorophenyl group) boric acid three (normal-butyl) ammoniums,

Four (pentafluorophenyl group) boric acid N, N- dimethyl puratized agricultural sprays,

Four (pentafluorophenyl group) boric acid N, N- diethyl puratized agricultural sprays.

Suitable for the preferred type being used together with metallocene complex co-catalyst include containing cation and the moon from The ionic compound of son, wherein the anion has the substituent group of at least one part comprising active hydrogen.

Described in WO 98/27119, related part is incorporated by reference into text the suitable cocatalysts of the type.

The example of such anion includes：

Triphenyl (hydroxy phenyl) borate

Three (p-methylphenyl) (hydroxy phenyl) borates

Three (pentafluorophenyl group) (hydroxy phenyl) borates

Three (pentafluorophenyl groups) (4- hydroxy phenyls) borate

The example of suitable cation for such co-catalyst includes triethyl ammonium, triisopropyl ammonium, diethyl Ylmethyl ammonium, dibutylethyl ammonium and analog.

Specially suitable is with those of longer alkyl chain cation, such as dihexyl decyl methyl ammonium, double octadecanes Ylmethyl ammonium, double tetradecylmethyl ammoniums, bis- (hydrogenated tallow alkyl) methyl ammoniums and analog.

The particularly preferred co-catalyst of this type is three (pentafluorophenyl group) 4- (hydroxy phenyl) boric acid alkylammoniums.It is especially excellent The co-catalyst of choosing is bis- (hydrogenated tallow alkyl) methyl ammoniums of three (pentafluorophenyl groups) (4- hydroxy phenyls) boric acid.

About such co-catalyst, preferred compound is three (pentafluorophenyl group) -4- (hydroxy phenyl) boric acid alkane The reaction product of base ammonium and organo-metallic compound (such as trialkylaluminium or aikyiaiurnirsoxan beta such as four isobutyl aluminium alkoxides).This type The suitable cocatalysts of type disclose in WO 98/27119 and WO 99/28353.Preferred trialkyl aluminium compound is triethyl group Aluminium or trimethyl aluminium, the latter are particularly preferred.Contact between borate and trialkyl aluminium compound is usually in a suitable solvent At room temperature and more preferably carried out at a temperature of -25 DEG C -10 DEG C of range.Preferred solvent for contact is arsol, special It is not toluene.

Being used to prepare the catalyst of the new copolymer of the present invention can compatibly support.

Suitable carrier material includes inorganic, metal oxide or can alternatively use polymeric carrier, such as poly- second Alkene, polypropylene, clay, zeolite etc..

With the catalyst-loaded most preferably carrier material being used together according to the method for the present invention be with 20-70 μm, It is preferred that the silica of 30-60 μm of median diameter (d50).Such specially suitable carrier is Grace Davison D948 or 2408 silica of Sylopol and PQ Corporation ES70 or ES757 silica.

Carrier material can be through heat-treated and/or chemical treatment to reduce the water content or hydroxy radical content of carrier material. Usual chemical dehydrator is reactive metal hydride, aluminium alkyl and halide.Before it is using carrier material, Ke Yi In an inert atmosphere through being subject to processing at 100 DEG C -1000 DEG C and preferably at 200-850 DEG C.

Porous carrier preferably uses organo-metallic compound, preferably organo-aluminum compound and most preferably three alkane in retarder thinner Base aluminium compound pre-processes.

Carrier material is located at a temperature of -20 DEG C to 150 DEG C and preferably 20 DEG C to 100 DEG C with organo-metallic compound in advance Reason.

Other possible catalyst include the metallocene complex handled with polymerisable monomer.We apply for WO earlier 04/020487 and WO 05/019275 describes the supported catalyst composition that wherein polymerisable monomer is used for catalyst preparation.

The polymerisable monomer for being suitable for the invention this aspect includes ethylene, propylene, 1- butylene, 1- hexenes, 1- octenes, 1- Decene, styrene, butadiene and polar monomer are such as vinyl acetate, methyl methacrylate.Preferred monomer be with Those of 2-10 carbon atom, especially ethylene, propylene, 1- butylene or 1- hexenes.Most preferred comonomer is 1- hexenes.

In being used to prepare the preferred method of composition of the present invention, in the outlet of further polymer reactor, collection includes The slurry of the composition of the present invention.The composition can be detached by any known mode from suspension.Usually, suspension is subjected to Pressure expansion (final expansion) from composition so that remove diluent, ethylene, α-alkene and any hydrogen.

The composition of the present invention is usually mixed into particle, can optionally be used subsequently to article of manufacture.Mixing apparatus and Condition is well known to those skilled in the art.

Composition prepared in accordance with the present invention can be mixed with the common processing additives for polyolefin, such as stabilizer (antioxidant and/or anti-UV agent), antistatic agent and processing aid and pigment.Example includes the stearic acid as acid neutralizing agent Calcium or stearic zinc, as the Irgafos 168 of processing antioxidant, and as thermal oxidation resistance agent Irganox 1010 or 1076, and the metallic salts such as magnesium chloride being hydrated is to reduce the yellow colour index of polymer。

Embodiment

The meaning of the symbol used in these embodiments and the unit of the expression property is described below and for surveying The method for measuring these properties.

Melt index

Melt index MI₂With HLMI according to ISO1133 at a temperature of 190 DEG C respectively 2.16kg and 21.6kg load under It determines, is indicated with g/10min.

Density

The density of polyethylene is measured according to ISO 1183-1 (method A) and sample panel is made according to ASTM D4703 (condition C) It is standby, wherein it is cooled to 40 DEG C from 190 DEG C under the cooling rate of 15 DEG C/min under stress.

Soluble matter

Soluble matter is on 1.5g samples by being extracted 2 hours under being flowed back at 68 DEG C using n-hexane with Kumagawa extractors It measures.C₆The weight of soluble matter determines that drying is any micro to remove in an oven for sample by extracting front and back weight difference N-hexane.

Spiral flow

Spin test uses the FANUC S2000i 150A injection moulding apparatus with spiral mould to carry out.Spiral mould is tool There are the traditional dies of the width of the helical cavity of circular form, the thickness of 1mm and 10mm.The length of flow length flowed out from center Spiral flow channel measurement；Generally along flow path etched recesses to help to identify the length that polymer flows in mold.? Mold is filled using rotary screw in pipe, is operated with constant speed (injection speed).In the filling stage of mold, the spy on screw rod Determine injection pressure to be gradually increased until it reaches 1000 bars, is set as being connected to pressure in injection moulding apparatus.At this pressure, screw rod Stop and screw speed is reduced to 0, terminates the filling stage.There is no the holding stages after the filling stage (not to keep pressure Or the retention time), and polymer spiral starts to be quickly cooled down until mold can be opened to project the solid spiral of polymer.It is poly- The performance for closing object is assessed based on length of flow.Length of flow data are presented with millimeter.Injecting condition is shown below：

The specific injection pressure of connection：1000 bars

Without keeping pressure

Screw diameter：32mm

Screw rod rotary speed：80rpm

Screw of injection speed：100mm/s

Temperature in cup and die orifice：250℃

The temperature of all areas：250℃

Mold temperature：40℃

Cooling time：20s

Cycle time：30s

Dynamic rheological analysis

Dynamic rheological property measure according to ASTM D 4440 with 25mm diameter parallel plates dynamic rheometer (for example, ARES it is carried out under an inert atmosphere with dynamic mode on).For all experiments, suitably stabilized (will added with antioxidant Add agent), compression molding sample be inserted on parallel-plate before, rheometer thermostabilization at least 30 minutes at 190 DEG C.The plate with It is closed afterwards with the positive normal power recorded in instrument to ensure well to contact.At 190 DEG C after about 5 minutes, plate is lightly pressed Tightly and by the superfluous polymer at the circumference of plate cut.Allow to be used for thermostabilization after 10 minutes and normal force is made to be decreased back to 0.It is, all measure is carrying out after sample balances about 15 minutes at 190 DEG C and is being run under the covering of complete nitrogen.

Originally two strain sweep (SS) experiments carry out at 190 DEG C in full rate (such as 0.01-100rad/s) model Lower measurement linear viscoelasticity strain is enclosed, 10% torque signal of the subordinate (lower scale) for being more than frequency changer will be generated. First SS experiments are carried out with the low application frequency of 0.1rad/s.The experiment is used to measure the sensitivity of torque under low frequency.Second SS is tested to be carried out with the high frequency that applies of 100rad/s.This ensures that selected apply strains well in the linear viscous of polymer In Hookean region, to vibrate flow measurement not structure change of induced polymer during experiment.In addition, time sweep (TS) Experiment is carried out with the low application frequency of 0.1rad/s to check that sample exists under selected strain (such as tested and determined by SS) Stability during experiment.

Shear shinning index SHI

Shear shinning index (SHI) is according to Heino (" Rheological characterization of polyethylene fractions（The rheology characteristic of polyethylene part）" Heino, E.L., Lehtinen, A., Tanner J., Seppälä, J., NesteOy, Porvoo, Finland, Theor. Appl. Rheol., Proc. Int. Congr. Rheol, 11th (1992), 1,360-362, and " The influence of molecular structure on some rheological properties of polyethylene（Molecular structure to polyethylene one The influence of a little rheological equationms of state）", Heino, E.L., Borealis Polymers Oy, Porvoo, Finland, Annual Transactions of the Nordic Rheology Society, 1995.) it calculates.

SHI values pass through the calculated complex viscosities il under the constant shear stress of 1 and 100kPa respectively₁And η₁₀₀It obtains.Shearing Thinning index SHI_(1/100)It is limited to two viscosities ils₁And η₁₀₀Ratio.

ESCR (in PCO1810 lid designs)

Environmental stress crack resistance (ESCR) is surveyed on the lid prepared according to lid design PCO1810 with 2.9g weight It is fixed.Lid is rotated to the torque of 25cm.kg on the pre-filled PET- prefabricated components of water.Hydrostatic pressure in PET- prefabricated components It is kept using the flexible pipe for being connected to its end.Cover is completely submerged in the 10wt% solution of Igepal CO360.Experiment exists It is carried out at 6 bars and 40 DEG C：Measurement occurs pressure drop due to leakage and (causes) the time it takes by covering cracking.Experiment is at 10 Progress is covered, and ESCR results are calculated using the arithmetic mean of instantaneous value of 10 test results.

All PCO1810 lids design covers pass through the Nestal Synergy machines in the Antonin molds with 12 lid chambers It is molded and generates on device 1000-460.Injecting condition is shown below：

Screw diameter：40mm

Injection speed value：8mm/s lasts 1.48s, and subsequent 23mm/s lasts 0.37s, and subsequent 36mm/s lasts 0.11s, Subsequent 48mm/s lasts 0.25s, and subsequent 66mm/s lasts 0.15s, and subsequent 49mm/s lasts 0.09s, and subsequent 16mm/s lasts 0.17s, subsequent 8mm/s last 0.23s.

Injection pressure：1400 bars

The temperature of all areas：220℃

Mold temperature：10℃

- 10 DEG C of cooling time：1.75s

Keep pressure：1290 bars

Keep pressure time：0.25s

Gel osmoticing chromatogram analysis for molecular weight distribution determination

Without the modified apparent molecular weight distribution of long chain branching and associated averages, pass through gel infiltration (or size exclusion) Chromatography uses the column WATERS with 4 30cm length according to ISO16014-1, ISO 16014-2 and 16014-4 STYRAGEL HMW 6E and 1 4.6 x 30mm of guard column Waters Styragel and differential refractometer detector Polymer Laboratories PL 220 are determined.

Solvent used is the 1,2,4- trichloro-benzenes with stabilized 150 DEG C of BHT that 0.2g/ rises concentration.0.8g/ rises concentration Polymer solution prepared at 160 DEG C and last 1 hour, and be only stirred at last 30 minutes.Nominal injection volume is set It is 1ml/min in 400 μ l and nominal flow rate.

Relative calibration is built using 13 kinds of narrow molecular-weight linear polystyrene standards objects：

Record the elution volume V of each PS reference substances.Then PS molecular weight is turned using following Mark Houwink parameters It is melted into PE equivalents：

PE=0.725 10-4 dl g-1 α PS=0.707, kPE=3.92.10-4 the dl g-1, α of kPS=1.21.

Calibration curve Mw Pp=f (V) are then fitted with order-1 linear equation.All calculating are with from Waters's 2 softwares of Empower carry out.

A) catalyst

Reagent used

TEA triethyl aluminums

TMA trimethyl aluminiums

TiBAl triisobutyl aluminiums

Ionic compound A [N (H) Me (C_18-22H_37-45)₂][B(C₆F₅)₃(p-OHC₆H₄)]

Complex compound A (C₅Me₄SiMe₂N^tBu)Ti(η⁴- 1,3- pentadienes)

The silica ES757 that 10.0kg into 90 liters of hexanes is previously calcined at 400 DEG C 5 hours (derives from PQ Corporation in), 19.28 0.5mol Al/ being added in hexane rise TEA.After being stirred 1 hour at 30 DEG C, two are allowed Silica is stood and supernatant is removed by being decanted.Then weigh with 130 liters of hexane wash residual objects five times and in 130 liters of hexanes New pulp.1 liter solution & stir slurries of the Statsafe 2500 (deriving from Innospec) in pentane (2g/l) is then added 15min。

The toluene solution (10.94%wt) of 8.19kg ionic compounds A is cooled to 5 DEG C and 342g TMA are added through 10min Hexane solution (1mol/L).After futher stirring 20min at 5 DEG C, transfer the solution into containing from previous steps The slurry that silica is handled through TEA, lasts the time of 80min.Gained mixture well stirs 3 hours at 20 DEG C.Then The n-heptane solution (9.51%wt) that 2.19kg complex compounds A is added lasts 30 minutes time, and the mixture is good again at 20 DEG C Agitation 3 hours.It then allows slurry to stand and supernatant is removed by being decanted.Then three times simultaneously with 150 liters of hexane wash residual objects The green powder until the flowing that gains freedom is dried at 45 DEG C in a vacuum.

[Al]=1.11mmol/g

[Ti]=38µmol/g

[B]=48µmol/g

B) Composition

Composition according to the present invention is manufactured in 40L loop reactors after prepolymerization, in the multistage in suspension In reaction at two be respectively volume 200L and 300L loop reactor in carry out.Reactor is connected in series with, and will come from pre-polymerization The slurry for closing reactor is transferred directly to the first loop reactor.Second servo loop reactor passes through equipment and the first loop reactor It separates, the equipment allows to be carried out continuously pressure reduction.Embodiment 1 and CE5 are employed as hexane and the conduct of diluent The 1- butylene of comonomer, embodiment 2-4 are employed as the isobutene of diluent and the 1- hexenes as comonomer.

Diluent, ethylene, hydrogen, TiBAl (10ppm) and the catalyst for preparing as described above are introduced continuously into pre-polymerization It closes in reactor and carries out the polymerization of ethylene in the mixture to form prepolymer (P).Prepolymer (P) will be additionally comprised Mixture is continuously withdrawn from the pre-polymerization reactor and is introduced into first reactor.By other diluent, ethylene, hydrogen, TiBAl (10ppm) and optional alpha-olefin comonomer be introduced continuously into the first loop reactor and in the mixture into Row polymerisation is to obtain the first ethylene polymer fraction (A).The mixture of first polymer (A) will be additionally comprised from described First reactor is continuously withdrawn and withstanding pressure reduces (~ 45 DEG C, 6.0 bars), to remove at least part hydrogen.Then and second It is anti-that the gained mixture at least partly sloughing hydrogen is introduced continuously into the second polymerization by alkene, comonomer, diluent and hydrogen simultaneously It answers in device, and carries out the copolymerization of ethylene and alpha-olefin wherein to form ethylene/alpha-olefin copolymer part (B).Containing poly- The suspension of polymer composition is continuously withdrawn from second reactor and the suspension is subjected to last pressure reduction, to flash off Existing diluent and reactant (ethylene, comonomer and hydrogen).In the case that hexane is used as diluent wherein, last After pressure reduction, steam is additionally incorporated to promote diluent to evaporate.Then make the composition dry and deaerate to remove residual Hydrocarbon and as dry powder recycle.Other polymerizing conditions and copolymer property illustrate in tables 1 and 2.

Then by polymer powder be transferred to Werner and Pfleiderer ZSK40 double screw extruders and with it is following Additive packet mixes：

Tinuvin 622：0.6g/kg

Calcium stearate：2g/kg

Irgafos 168：1.5g/kg

Comparative example C6 and C7 are bimodal total comprising homopolymer part (A) and Ethylene/1-butene copolymer portion (B) Ionomer compositions, and prepared according to the introduction in EP 1441959A.

1-polymerizing condition of table

2-polymer property of table

Figures 1 and 2 show that the improvement balance of the property of the embodiment of the present invention, such as high ESCR, low soluble matter are horizontal and high Spiral flow valuve, indicate injection moulding process in good workability.

Claims

1. polyethylene composition, with 950-960kg/m³Density, the shear shinning index SHI of 4-12_(1,100), 0.2-2g/ The melt index MI of 10min₂And E>200-SF at 250 DEG C/1000 bars/100mm/s with mm measurement spiral flow SF and With the relationship between the environmental stress crack resistance E of hour measurement, wherein the composition includes the vinyl polymerization of 48-62wt% The ethylene copolymer (B) of object (A) and 38-52wt%, ethylene copolymer (B) have the weight average molecular weight higher than ethene polymers (A) Both Mw and ethene polymers (A) and ethylene copolymer (B) have reversed comonomer distribution so that comonomer contains Amount is improved with the raising of molecular weight in unitary part.

2. the relationship between composition according to claim 1, wherein SF and E is E>370-2SF.

3. the relationship between composition according to claim 2, wherein SF and E is E>540-3SF.

4. polyethylene composition, with 950-960kg/m³Density, the shear shinning index SHI of 4-12_(1,100), 0.2-2g/ The melt index MI of 10min₂, E> (9800-36SF-1000MI₂)/60 at 250 DEG C/1000 bars/100mm/s with mm degree The spiral flow SF of amount, with hour measurement environmental stress crack resistance E and at 190 DEG C under the load of 2.16kg according to ISO The 1133 melt index MI measured with g/10min₂Between relationship.

5. composition according to claim 4, wherein SF, E and MI₂Between relationship be E> (11000-36SF-1000MI₂)/ 60。

6. composition according to claim 5, wherein SF, E and MI₂Between relationship be E> (12000-36SF-1000MI₂)/ 60。

7. composition according to claim 1, the SHI with 4-10_(1,100)。

8. composition according to claim 7, the SHI with 4-8_(1,100)。

9. composition as claimed in one of claims 1-8, the molecular weight distribution measured by gpc analysis with 5-13 Mw/Mn。

10. composition according to claim 9, the molecular weight distribution mw/mn measured by gpc analysis with 6-12.

11. composition according to claim 10, the molecular weight distribution mw/mn measured by gpc analysis with 7-11.

12. composition as claimed in one of claims 1-8, with S<The SF of 0.1SF and with g/kg measure C6- can Relationship between molten object S.

13. the relationship between composition according to claim 12, wherein SF and S is S< 0.1SF-2.5.

14. composition according to claim 13, the relationship between SF and S is S< 0.1SF-5.

15. composition as claimed in one of claims 1-8, it includes the ethene polymers of 50-60wt% (A) and 40- The ethylene copolymer (B) of 50wt%, ethylene copolymer (B) have the weight average molecular weight Mw higher than ethene polymers (A).

16. composition as claimed in one of claims 1-8, wherein ethene polymers (A) are copolymer, and have 969- 974kg/m³Density and 10-800g/10min MI₂。

17. composition as claimed in one of claims 1-8, with 950-954kg/m³Density and 1-2g/10min MI₂。

18. composition according to claim 17, with 951-954kg/m³Density and 1.2-1.8g/10min MI₂。

19. composition as claimed in one of claims 1-8, with 954-960kg/m³Density and 0.1-1g/10min MI₂。

20. composition according to claim 19, with 955-959kg/m³Density and 0.2-0.8g/10min MI₂。

21. the density of composition according to claim 17, wherein ethylene copolymer (B) is 919-936kg/m³, and ethylene copolymer The HLMI of object (B) is 3-6g/10min, and wherein HLMI is the high load melt index determined under 21.6kg loads.

22. the density of composition according to claim 21, wherein ethylene copolymer (B) is 924-932kg/m³。

23. the HLMI of composition according to claim 21, wherein ethylene copolymer (B) is 4-5g/10min.

24. the density of composition according to claim 19, wherein ethylene copolymer (B) is 929-947kg/m³, and ethylene copolymer The HLMI of object (B) is 0.2-2g/10min, and wherein HLMI is the high load melt index determined under 21.6kg loads.

25. the density of composition according to claim 24, wherein ethylene copolymer (B) is 934-942kg/m³。

26. the HLMI of composition according to claim 24, wherein ethylene copolymer (B) is 0.5-1.5g/10min.